121 Deposition of microplastics associated with bioaccumulation of heavy metals in human lungs: adsorption and mobilization of metals via microplastics

Abstract Background Bioaccumulation of airborne micro- and nano plastics (MNPs) in lung tissues and the effect of tobacco smoking on deposition of MNPs are unknown. We hypothesized that smoking leads to enhanced chelation of heavy metals with airborne MNPs leading to accentuated lung bioaccumulation, thereby leading to lung pathologies. Methods Age (20 to 75 yr) and sex-matched archival lung tissue samples from smokers (n = 9) and non-smokers (n = 10) were procured and quantified to assess: (a) the levels of MNPs by pyro-GC/MS and (b) heavy metals by ICP-MS. Furthermore, to establish if there exists a correlation between MNP deposition and disease occurrence in current smokers, tissue samples from age-matched patients with COPD (n = 4) and IPF (n = 4) underwent pyro-GC/MS analyses. Results A relatively higher level of MNPs were found in the lungs of smokers (43.67 mcg/gm) as compared to non-smoker (34.53 mcg/gm) upon pyro-GC/MS analyses. We observed a marked increase in the levels of polyethylene (PE; P 0.0076), polycarbonate (PC; P 0.0947) and nylon6 (N6; P 0.0653) polymers in the lungs of smokers as compared to non-smokers. Metal analyses showed a significant (P 0.0001) increase in the levels of cadmium (Cd) in the lungs of smokers with the levels of deposited Conclusions Our results show that smoking promotes bioaccumulation of certain MNPs (PE) with heavy metals (Cd) which may lead to adverse lung effects in smokers.